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Landé Pauli, Dirac and Spin
Published in Caio Lima Firme, Quantum Mechanics, 2022
The Dirac equation is a relativistic wave equation which describes the electron-spin. Whereas Heisenberg’s matrix mechanics and Schrödinger’s wave mechanics can be considered as free field theory, Dirac included both the electromagnetic field and electric charge matter as quantum mechanical variables. The wave functions of Dirac equation are vector of four complex numbers, bispinors. The Dirac equation can be written as: (βmc2+c∑n=13αnpn)ψ(q,t)=iℏ∂ψ(q,t)∂t
Bimodal Reaction Sequences in Oxidation of Hydrogen and Organic Compounds with Dioxygen
Published in Robert Bakhtchadjian, Bimodal Oxidation: Coupling of Heterogeneous and Homogeneous Reactions, 2019
In modern physics, however, the problem of the origin of charge is a subject of both experimental and theoretical investigations, as an intrinsic property of the subatomic particles. Positron is a subatomic particle that has the same mass and spin as an electron but a positive charge. The positron, also named the antielectron, is the first antimatter particle discovered. The existence of antimatter was predicted by the Dirac equation, formulated in 1932 by Paul Dirac who as a result was awarded the Nobel Prize in Physics in 1936. In annihilation at the low-energy collision, an electron and positron pair produce two or more γ photons by the reaction.e−+e+→γ+γ
Implications of causality for quantum biology – I: topology change
Published in Molecular Physics, 2018
The Dirac equation, however, is limited to low energy situations where the number of particles does not change. The positron is predicted in Dirac theory because negative energy states appear in the spectrum of the Dirac operator. The Dirac equation does not directly predict the existence of electron–positron pair production. Such pair production, allowed in the multi-particle theory (quantum electrodynamics), provides the shepherding of causality: as long as energy-momentum can be conserved, different pairs of (quasiparticle) excitations are created at sufficient energies instead of causality violation. These excitations are polarisations of the quantum mass–spacetime continuum [11]. The pair creation changes the number of particles, so many-body techniques are required. The Dirac operator is merely a single-mode generator of the multi-mode description of the quantum mass–spacetime [11].